Plaster cast cutter



Sept. 16, 1947.A H; H'. sTRYKER 2.427,580

PLASTER CAST CUTTER Filed April 2, 1945 AITORNEYJ.

Patented Sept. i6, 54?

UNITED STATES PATENT OFFICE 9 Claims. (Cl. 30-166) 'I'his inventionrelates to improvements in plaster cast cutter.

The main objects of this invention are:

First, to provide a cutting implement which is highly eicient forcutting casts and the like and at the same time is not likely to injurea patient or the user or garments or fabric with which it may come incontact.

Second, to provide a cutting implement which has a wide range of usesand which is very convenient to use and is compact and durable.

Objects relating to details and economies of the invention will appearfrom the description to follow. The invention is dened and pointed outin the claims.

A preferred embodiment of the invention is illustrated in theaccompanying drawing, in which:

Fig. 1 is a side elevation of an implement embodying my invention in adesirable form.

Fig. 2 is a fragmentary view in section on line 2-2 of Fig. 1, thecutter being partially broken away and partially shown by dotted lines.

Fig. 3 is a sectional view on line 3-3 of Fig. 1.

Fig. 4 is a fragmentary view mainly in longitudinal section on line 4--4of Fig. 3.

Fig. 5 is a fragmentary perspective view with the cutter head removed.

In the embodiment of my invention illustrated in the accompanyingdrawing, I represents the motor casing, 2 the circuit connection theretoand 3 a control switch. The motor casing is provided with a tubular endextension 4 constituting part of one end member of the motor housing 5,this extension being adapted as a hand-hold or grip. At its outer endthe extension is provided with a bearing 6 for the motor shaft 1.

The motor shaft is provided with a crank pin or eccentric pin 8 havingan anti-friction roller 9 mounted thereon. The shaft is preferablyprovided with a counter-weight I0 for the crank pin and its roller, thepurpose being to minimize vibration by counterbalancing the offset oreccentrically disposed crank pin element.

The cutter head II is provided with a bore I2 receiving the end I3 ofthe extension 4, this end being somewhat enlarged in the embodimentillustrated. The head member has a longitudinal slot I4 providing a pairof ears I5 receiving the clamping screws I6 so that the cutter head isdetachably secured upon the housing extension 4. The cutter head ischambered at Il to receive the crank pin and counterweight, a closure I8being provided for the end of the housing extension, this closure beingpolygonal in shape and fitting 2 Y Y within a recess I9 providedtherefor, a sealing disk 20 being arranged on the inner side of thisclosure member.

The head member is provided with a. face plate 2| secured by screws 22.The body of the cutter head and the face plate have aligned bearings 23and 24 provided with bushings 25 for the cutter shaft 26. This cuttershaft is provided with an arm 21 secured to the shaft by the pin 28 andhaving a longitudinal slot 29 engaged by the crank pin roller 9. Thisslot is of Such dimensions as to slidably embrace the crank pin rollerand fits the same relatively closely so that there is no lost. motionand noise resulting from operation.

The cutter 30 is preferably in the form of a disk having a saw-toothedge 3l, the teeth being preferably relatively fine as shown in Fig. 2.

'I'he throw or eccentricity of the crank pin isA such that the stroke ofthe cutter is relatively short. The implement shown in Fig. 1 isl afullsize commercial implement and has a, stroke of approximatelyone-eighth of an inch. 'I'his is indicated by the lines 33 in Fig. 2.

The end of the cutter shaft is reduced at 34 to receive the clampingsleeve 35, the cutter' being arranged at the outside of this sleeve andclamped against it by means of the clamp member 36 and the screw 31tapped into the end of the shaft.

My improved implement is highly efficient in the cutting of casts orother hard substances but yielding surfaces or materials are not cut orinjured thereby in the event the cutter should accidentally contact ytheskin of a person and `it does not cut fabrics or other objects unlessthey are supported by a fairly rigid backing.

My improved implement has, however, a wide range of uses such forexample as cutting bone, plastics, wood and even metal.

I have illustrated and described my invention in a very practicalembodiment thereof. I have not attempted to illustrate or describe otherembodiments or adaptations as it is believed that this disclosure willenable those skilled in the art to embody or adapt my invention as maybe desired.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent. is:

1. An implement for cutting casts and the like comprising a motorprovided with a casing hav ing a forwardly projecting tubular endextension adapted as a shaft housing and as a grip and 3 provided with amotor shaft bearing at its outer end, a motor shaft disposed within saidhousing and supported at its outer end in said bearing, an eccentric pinon the end of said shaft provided with an anti-friction roller, saidshaft being provided with a counterbalance for said pin and roller, aclosure for the outer end of said housing extension disposed on theinner side of said counterbalance and roller, a chambered cutter headmounted on the end of said housing extension. said cutter head beingprovided with a bearing disposed below said housing extension, a cuttershaft disposed in said bearing in said head and provided .vith an armslotted to receive said roller on said pin, a face plate for said cutterhead provided with a bearing supporting the cutter shaft at the outerside of said arm, and a toothed cutter secured to the end of said shaft.

2. An implement for cutting casts and the like comprising a motorprovided with a casing having a forwardly projecting tubular endextension adapted as a shaft housing and as a grip and provided with amotor shaft bearing at its outer end, a motor shaft disposed within saidhousing and supported at its outer end in said bearing, an eccentric pinon the end of said shaft provided with an anti-friction roller, saidshaft being provided with a counterbalance for said pin and roller, achambered cutter head mounted on the end of said housing extension, saidcutter head being provided with a bearing disposed below said housingextension, a cutter shaft disposed in said bearing in said head andprovided with an arm slotted to receive said roller on saidpin, a faceplate for said cutter head provided with a bearing supporting the cuttershaft at the outer side of said arm, and a toothed cutter secured to theend of said shaft.

3. An implement for cutting casts and the like comprising a motorprovided with a casing having a forwardly projecting tubular endextension adapted as a shaft housing and as a grip and provided with amotor shaft bearing at its outer end, a motor shaft disposed within saidhousing and supported at its outer end in said bearing, an eccentric pinon the end of said shaft provided with an anti-friction roller, achambered cutter head mounted on the end of said housing extension, saidcutter head being provided wtih a bearing disposed below said housingextension, a cutter shaft disposed in said bearing in said head andprovided with an arm slotted to receive said roller on said pin, a face-plate for said cutter head provided with a bearing supporting thecutter shaft at the outer side of said arm, and a toothed cutter securedto the end of said shaft.

4. An implement for cutting casts and the like comprising a motorprovided with a casing having a forwardly projecting tubular endextension adapted as a shaft housing and as a grip and provided with amotor shaft bearing at its outer end, a motor shaft disposed Within saidhousing and supported at its outer end in said bearing, an eccentric pinon the end of said shaft provided with an anti-friction roller, achambered cutter head having a bore receiving the end of said housingextension, said head being split at one side of said bore and providedwith clamping screws whereby it is clamped upon said extension,

said cutter head being provided with a bearing disposed below saidhousing extension, a cutter shaft disposed in said bearing in said headand provided with an arm slotted to receive said roller on said pin, aface plate for said cutter head provided with a bearing supporting thecutter shaft at the outer side of said arm, and a toothed cutter securedto the end of said shaft.

5. An implement for cutting casts and the like comprising a, motorprovided with a casing having a forwardly projecting tubular endextension adapted as a shaft housing and as a grip and provided with amotor shaft bearing at its outer end, a motor shaft disposed within saidhousing and supported at its outer end in said bearing, an eccentric pinon the end of said shaft provided with an anti-friction roller, saidshaft being provided with a counterbalance for said pin and roller, achambered cutter head mounted on the end of said housing extension andprovided with a cutter shaft bearing, an oscillating cutter shaftdisposed in said bearing and provided with an arm slotted to receivesaid roller on said pin, the width of the slot being such as to providea relatively close t for said roller while permitting free rotationthereof and free movement longitudinally of the slot, and a toothedcutter on and oscillated by said shaft, the eccentricity of said crankpin being such that the cutter is actuated with a relatively shortoscillating stroke.

6. An implement for cutting casts and the like comprising a motorprovided with a casing having a forwardly projecting tubular endextension adapted as a shaft housing and as a grip and.

provided with a motor shaft bearing at its outer end, a motor shaftdisposed within said housing and supported at its outer end in saidbearing, an eccentric pin on the end of said shaft provided with ananti-friction roller, said shaft being` provided with a counterbalancefor said pin and roller, a chambered cutter head mounted on the end ofsaid housing extension and provided with a cutter shaft bearing, anoscillating cutter shaft disposed in said bearing and provided with anarm slotted to receive said roller on said pin, and a toothed cutter onand oscillated by said shaft.

7. An implement for cutting casts and the like comprising a motorprovided with a casing having a forwardlyprojecting tubular endextension adapted as a shaft housing and as a grip and provided with amotor shaft bearing at its outer end, a motor shaft disposed within saidhousing and supported at its outer end in said bearing, an oscillatingcrank pin on the end of said shaft, a chambered cutter head on the endof said housing extension provided with a bearing disposed below saidhousing extension, a cutter shaft disposed in said bearing in said headand provided with an arm coacting with said pin, and a toothed cutter onand oscillated by said shaft, the eccentricity of said crank pin beingsuch that the cutter is actuated with a relatively short oscillatingstroke of the order of one-eighth of an inch.

8. An implement for cutting casts and the like comprising a motorprovided with a casing having a forwardly projecting tubular endextension adapted as a shaft housing and as a grip and provided with amotor shaft bearing at its outer end, a motor shaft disposed within saidhousing and supported at its outer end in said bearing, a crank pin onthe end of said shaft, a. chambered cutter head on the end of saidhousing extension provided with a bearing disposed below said housingextension, an oscillating cutter shaft disposed in said bearing in saidhead and provided with an arm coacting with said pin, and a toothedcutter on and gscillated by said shaft, the eccentricity of said crankpin being such that the cutter is actuated with a relatively shortoscillating an arcuate path about said rockshait and in a l5 1,763,730

plane substantially, at right angles to said rotary and rockshafts.

HOMER H. STRYmSR.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 436,804 Roberts Sept. 23, 18901,951,880 Niederhofer Mar. 20, 1934 2,163,018 Bernier June 20, 1939 VonLackum June 17, 1930

